Apparatus for freezing comestibles



" June 25, 1946.- N. SHARPE 2,402,921

APPARATUS FOR FREEZING COMESTIBLJES Filed Aug. 18, 1942 3 Sheets-Sheet l June 25, 1946. N. SHARPE APPARATUS FOR FREEZING COMESTIBLES Filed A 18, 1942 s Sheet-Sheet 2 Jae 47 I fiune 25, 1946.

N. SHARPE APPARATIiS FOR FREEZING C OMESTIBLES Filed Aug. 18, 1942 3 Sheets-Sheet 3 and the evaporator coil.

AFPATUS F03. FREEZING ,COMEES'EBLES Norman Sharpe, San Luis Obispo, Calif.

Application August 18, 1942, Serial No. 455,229 12 claims. (or. 62-4 92) This invention relates generally to apparatus for freezing comestibles, but is directed more particularly to apparatus wherein a two stage refrigerating system is used in combination with an improved type of combination condenser and evaporator or condenser and precooling coil.

. The primary object of the invention'is to provide a. simple, comparatively cheap yet highly efiicient apparatus for freezing foods.

Another and further object is to provide an apparatus carrying out the improved method which apparatus calls for the minimum space requirements, little if any insulation'of the re= frigerant-carrying conduits, and an apparatus requiring fewer parts than those required normally in the practice of freezing food's, all to the end that the apparatus is convenient of use and installation and comparatively cheap and simple of manufacture, yet highly efficient in operation.

Other specific objects, novel features of construction and improved results of the apparatus will appear from the following description and accompanying drawings in which an apparatus capable of performing the present improved method is described and illustrated.

Inthe drawings:

Fig. 1 is a. longitudinal vertical sectional view through the refrigerating cabinet taken on the line l-l of Fig. 2 looking in the direction in-- dicated by arrows, parts oi the refrigerating system being shown in full line and exterior of the cabinet.

Fig. 2 is a transverse vertical sectional view through the refrigerating cabinet, the section being taken on line 2-4 of Fig. 1 looking in the direction indicated by arrows.

Fig. 3 is a horizontal sectionalview of the refrigerating cabinet, the view being taken on the line or Fig. 1 looking in the direction indicated by arrows.

Fig. 4 is a side view, partly in vertical section or the combined condenser and precooling coil Fig. 5 is a plan view of the coils illustrated in Fig. 4 of the drawings.

U similar reference numerals and characters to dte like parts, an apparatus found suitable for practicing the present improved methodwillnow'be described. A dtes a closed cabinet or housing composed of a top l, a front wall 2, a rear wall 3, a bottom wall 4 and end walls 5 and B and a hopper I. All of the aforementioned walls including the bottom wall 8 and end wall 8 as well as'the front and rear walls and cover id of the hopper are insulated walls. They are ill be the space between the walls filled with a suitable insulating material 6 l.

Intermediate its length the cabinet is divided by a vertically disposed insulated-wall 12 at the op= posite sides of which are positioned what I have termed a precooli-ng chamber i3 and a quick freezing chamber id. Intermediate its length the wall I2 is provided with a horizontally disposed and extending opening it which provides communication between the chambers l3 and Hi for a purpose which will hereinafter appear.

The cabinet is provided with a second division wall it disposed at right angles'to the wall it and extending from the end 6 of the cabinet to the insulated interior wall H of the fromn food receiving bin it. This wall has its lower ends l9 and 26 stopping considerably short of the bottom 6 and top 8 of the cabinet. This wall divides each of the chambers l3 and is intermediate the extent of these chambers from the front towards the rear of the cabinet but permits free communicationin each of these chambers between the upper and lower ends thereof as the wall it in reality forms a passageway 20 providing communication between the upper end B and the lower end C of the chamber it and between the upper end D and the lower end E of the chamber id in which a similar passageway is formed.

An endless pervious conveyor 22, such as wire mesh, has one end within the lower end of the hopmr i while its opposite end extends through the opening it in the division wall l2 so that it will discharge into the quick freezing chamber across the quick freezing chamber id but is disposed in a horizontal plane beneath the top oi the first mentioned conveyor 22 so that it receives the discharge fromthe conveyor 22. The

conveyor it extends through an ope it in the interior well i! of the bin it to discharge into said bin. This conveyor is trained over a. driven pulley so and an'idler n.5, it and is driven by s second motor isrnotor is e 3 variable speed motor and is connected with the driven pulley by a belt 38.

Should it be found desirable both conveyors could be driven by a single motor but it is considered perferable to provide separate drive means for the conveyors as under certain conditions the process can be operated more advantageously by moving the food to be frozen through the precooling and quick freezing chambers at different speeds. In any event, the conveyors are at all times driven slowly irrespective of whether or not one may be driven slightly faster than the other.

The particular comestible to be frozen is of course placed in the feed hopper I and fed therefrom by gravity. To assist in directing the material to be frozen onto the feed end of the conveyor 22 a guide or deflector 34 is provided. A vertically sliding and adjustable gate 35 will cause the material to spread thinly upon the conveyor. A similar guideor deflector plate 36 is provided at the feed end of the conveyor 28 for assuring that the material discharged from the conveyor 22 is directed properly to the conveyor 28.

Both of the conveyors have-upwardly extending side walls or rails 31 to prevent the material being frozen from discharging or being displaced from the side edges of the conveyors.

It is quite essential to the economical and efiicient operation of the system that the cabinet be kept closed as tightly as possible. Accordingly the hopper I is provided with the aforementioned lid I and the bin I8 is provided with an insulated door 38. Additionally it is highly desirable to prevent to the greatest degree possible the circulation of air from the precooling chamber l3 into the quick freezing chamber I I and to prevent the ingress of air from the hopper I, when the cover thereof is removed, into the chamber I3 and to prevent the passage of air in the chamher into the bin I8. Accordingly a. horizontally pivoted .and vertically swinging door 39 is provided in the opening 40 through whichthe conveyor 22 extends into the binl; a similar door 4! is provided in the opening I5 through which the 1 and condensed out of the air on the combination conveyor 22 extends into the quick freezing chamber I4; and a third and similar door 42 is provided in the opening 29 through which the conveyor 28- extends into the upper end of the bin I8.

Hereinafter the refrigeration which takes place in the precooling chamber will be referred to as stage 1 and that taking place in the quick freez- .ing chamber I4 as stage 2. The power required chamber 14 which dictates that the division wall 52 between these chambers should be insulated.

For the above reason, in part, two separate distlnct conveyors have been used rather than a.

single conveyor extending from the hopper completely across both chambers I3 and I4 to the bin I8. A single conveyor would carry with it heat from the chamber I3 into the chamber I4. Also the two conveyors provide flexibility of speed of movement of the materials being treatedas has 'been pointed out, and additionally assist materially in preventing transmission of moisture "from the chamber Ilinto the chamber I4. Most of the (excess moisture of the material being frozen will be removed in the precooling chamber I4 condenser and precooling coil -R,- as will hereinafter more fully appear, but there might be a small amount of moisture left between the material being frozen and the conveyor belt 22. Were a single conveyor used this moisture would be not only conveyed into the quick freezing chamber I4 but would cause the material when passing through the quick freezingchamber to freeze to the conveyor.

Thus far none of the refrigerating equipment and arrangement of the system has been described other than the broad general reference to the combined condenser and precooling coil R. The refrigerating arrangement and equipment will now be described in detail.

A combination condenser and precooling coil R extends substantially entirely across the precooling chamber below the conveyor 22 and beneath it is positioned an electric or other suitably motorized fan d3 disposed for circulating air through the coil and through the perforate conveyor 22 and around and over the comestibles carried thereby.

The evaporator coil S extends substantially entirely across the quick freezing chamber Id and beneath it is positioned an electric or other suitably motorized fan 44 disposed to circulate air upwardly through the perforate conveyor 28 and around and over the comestibles. carried thereon.

The combination condenser and precooling coil, specifically illustrated in detail in Figs. 4 and 5 of the drawings, comprises a pair of headers 55 An inlet pipe 5! is connected to the header 45 which in turn is connected to the pipes 48 by short connecting conduits 52. The pipes 50 discharge through short conduits 53 into the header 48 from which leads the discharge conduit 54.

A pipe I00 is disposed within each pipe 48 and being of smaller diameter is arranged in spaced relationship to the interior walls of said pipe. An inlet conduit 56 is connected to the header 46 and the pipes I00 are connected to and constitute the discharge for said header. The pipes 55 extend outwardly through the ends 50 of the coil R or pipes 48 and are connected to a header I0| from which the pipes extend and are connected to the header I02 of the coil S. An expansion valve 68 is positioned in the line connecting the headers IOI and'I02. The pipes I00 extend outwardly from the header I02 in the form of a plurality of U bends to provide the aforementioned evaporator coil S. The evaporator coil S composed of the pipes I00 discharges into a header 51. from which extends a discharge pipe or conduit 58.

y In conformity with the usual andccmmon practice each of the coils is provided with a plurality of heat absorbing fins 69.

Referring to Fig. l of the drawings, 60 is a motor for driving a compressor 6| the discharge of which travels through the conduit 62 to a condenser 63 from which it passes by way of the pipe 5| to the header 45. Intermediate its length and in front of the header the pipe 5| is provided with an expansion valve 84. .The outlet pipe' 54' from the header 4!! of the coil R leads to" the inlet il of the compressor BI thus making a complete 5 closed fluid transmission system. It is understood or course that the system is filled with any suitable and well known refrigerant.

As for stage 2 of the system, 66 is a motor for driving a compressor 61 to the inlet side of which is connected the aforementioned pipe 56 which is connected to the aforementioned header 46. This stage of the refrigeration like the first st ge constitutes a closed liquid conduit system within which is confined any one of the well known refrigerants. From the header 46 the refrigerant passes through the pipe I in the pipe 48 of the coil R. Before being itself formed into a coil the pipe Mill is provided with anexpansion valve 68. Beyond the expansion valve 68 the pipe I 00 is provided with the aforementioned U shaped bends to constitute the evaporator coil S which discharges into the aforementioned header from which the refrigerant passes through the aforementioned conduit 58. This conduit is connected as at 69 to the intake side of the compressor 61.

By placing the compressor 69 within the chamber E it is unnecessary'to insulate any part of stage two of the system.

Although the fans are illustrated as creating an upward current of air through the coils they could be arranged to pull the air downwardly through the coils without departing from the inventive concept.

From the foregoing it will be seen that the combined condenser and precooling coil is in reality made up of the evaporator of stage 1 of the refrigerating system' and the condenser of stage 2 by the-fan M and caused to re-circulate in manner immediately before described.

After completing their travel through the precooling chamber the peas are deposited upon the conveyor in the quick freezing chamber l4 and here an air stream having a temperature below the freezing point, that is below 32 F., is circu lated through the pervious conveyor 28 and on and about the peas in the exact manner described in respect to the air circulation in the precooling chamber. That is to say, the fan it forces the air through the evaporator coil S upwardly through the conveyor and over the upper end of the cabinet division wall it and then downwardly behind said wall in the passageway 2i and under the lowerend of the division wall into the lower end 0 of the chamber. Here the air is pickedtup he It is to be understood of course that throughout thisperiod the liquid refrigerant is being continuously circulated throughout the system by the two cpmpressors 6i and 61. The evaporator S operates as does any other evaporator in a mechanical refrigerating system of the present type,

' but by reason of the combined condenser and preof the refrigerating system. Thus the condensatlon of the refrigerant of stage 2 of the system is eifected by the evaporation of the refrigerant of stage 1 of-the system.

Operation To a better understanding of the invention let it be assumed that the comestible to be frozen is peas. The peas would first be washed and blanched and then delivered to the feed hopper l the lid of which would promptly thereafter be replaced ,so as to render the cabinet as near airtight as possible. The peas under the force of gravity would be guidedon to the conveyor 22 by the guide 34 and WO'llldbe spread out on the conveyor by the adjustable gate or valve 35. With the conveyors in operation the peas would pass through the precooling chamber l3 and as they are moved slowly therethrough by the conveyor the fan 43 wouldforoe air through the combined condenser and precooling coil R and upwardly through the pervlous conveyor and around and over the peas. This air would escape over the upper end of thecabinet division wall It and pass downwardly behind said wall and forwardly beneath its lower end into the lower end E of the precooling chamber where it would be recirculated in the exact manner immediately before described. Thus cold air is continuously circulated through the conveyor and around and over the peas. No new air, with the exception of such possible unintended leakage as is present in the cabinet; would be added to the original air stream with the consequence that the operation is very eificient as no un-cooled air is being added to the circulating and refrigerating air stream.

The air which is circulated continuously lar path in the precooling chamber is of a temperature, as will be hereinafter explained, to nearly the freezing point, that is, approximately 32 F.

. through the conveyor and in more or less a circucooling coil a refrigerating system having definite and distinct advantages is obtained, as will now appear.

The compressed gas of stage 2 will enter the combined condenser and precooling coil B. through the header 6 and be circulated through the pipe Hill which is within the pipe 48 of the coilR and surrounded by the liquid refrigerant which is circulated through the pipe l8. The refrigerant within the pipe 48 is inthe stage 1 refrigerating system and after passing through the expansion valve 64 will enter the pipe 48 throughthe header 45. Heat from the air in the precooling chamber 13 will be carried to the refrigerant within th pip 48 through the coil evaporates between the interior walls of said pipe and the exterior walls of the pipe or tube 1 00.

That portion of the pipe 54 which is exterior of the cabinet-is insulated as at 12. Shou1d it be found desirable the compressor 6| could be placed in the cabinet and then this insulation would be unnecessary.

The coils R and S are illustrated as extending in' a vertical plane but it is to be understood that 'should it be found desirable they could extend.

in a horizontal plane, that is to say, the loops of the coils could be superimposed so that each coil loop would be disposed in a horizontal plane and extend in a horizontal direction parallel to the particular conveyor with which it is associated.

The apparatus illustrated is merely illustrative of one capable of practicing the method, and the invention accordingly is not to be limited by the specific constructional illustrations of the drawings other than to the extent that said constructions are embodied into and made a part of theinvention defined by the hereinafter following claims.

I claim: I

1. An apparatus for freezing comestibles or thelike comprising,' a pair of substantially closed chambers, means .fcr circulating an individual airstream in each of said chambers, a mechanical refrigerating system for cooling each of saiddischarging into the other and second chamber,

a conveyor in saidseocnd chamber forreceiving the discharge from said first named conveyor, the

conveyor of said second chamber extending across the chamber and the path followed by air circu-- lating therein and discharging at a point exterior of said second chamber, the refrigerating system of the first chamber being operable to chill the air stream therein to a temperature which will cool the comestibles to a temperature above but closely adjacentto their freezing point, the refrigerating system of the second chamber being operable to chill the air stream therein to a temperature below the freezing point of the comestibles, means to feed the comestibles to the conveyor of the first chamber, each of said refrigcrating systems including a refrigerating evaporator coil and a condenser coil, and the evaporator coil of that system serving'the less cold chamber being combined in heat exchange relationship with the condenser coil of that system serving the colder chamber.

2. A two stage refrigerating apparatus for I freezing comestibles or the like comprising, a

includesan evaporator refrigerating coil and a condenser coil, the evaporator coil of each system being disposed transverse the path followed by the stream of air circulated in its respective chamber, an individual conveyor extending across each of said chambers and the path followed by the air circulating therein at a point behind said evaporator coils, the conveyor in one of said chambers receiving comestibles from said comestible feed means and discharging into said second chamber and onto the conveyor of said second chamber, and the conveyor of said second chamber discharging said comestibles through said discharge passageway.

3. An apparatus constructed as defined in claim 1 wherein, a comestible feed means is provided with an opening through which the conveyor of the less refrigerated chamber extends and reoeives comestibles from. said feed means, said chambers being provided with an opening interconnecting the same, said last named conveyor extending through said opening and discharging comestibles onto the conveyor of the colder chamher, said colder chamber being provided with an opening through which its conveyor extends and discharges at a point exterior of said colder chamber, normally closed doors associated with each of the aforementioned openings. for reducing to the greatest degree possible the pasage of air through said openings, and said 'doors'belng movable to an open'position by th moving comestibles. f I

4. A construction such as defined in claim 1 wherein, an individual variable speed drive is provided for each of the individual conveyors.

5. A construction such as defined in claim 1 wherein, each of said refrigerating systems includes a compressor, and the condenser coil of that system serving the colder chamber having a substantial portion of its length disposed within and in spaced relation to the inner walls of the pipe constituting the evaporator of that refrigerating system serving the less cold chamber.

6. A construction such as defined in claim 1, wherein the closed chambers are insulated from the surrounding atmosphere and from one another.

'7. A two stage refrigerating apparatus for freezing comestibles or the like comprising, a closed cabinet having therein a pair of chambers in side by side relationship, each of said chambers provided with a partition stopping short of opposite walls of said chamber to. divide said chamber into two compartments having communication with one another at their ends, a conveyor extending across one of the compartments of each of said chambers, one of said chambers constituting a precooling and the other a quick freezing chamber, means in each of said chambers for circulating a continuous unbroken air stream from one compartment of said chamber to the other compartment thereof, a pair of mechanical refrigerating systems each of, which serves one of said compartments, each of said refrigerating systems including an evaporator refrigerating coiland a condenser, the refrigerating coil of each system being placed in the path followed by the air stream of its respective chamber, means to feed comestibles to the conveyor of the precooling chamber, the arrangement being such that the conveyor of the precooling chamber may discharge comestibles into the quick freezing chamber and onto its conveyor and the conveyor of the quick freezing chamber may discharge comestibles exterior of said quick freezing chamber, the refrigerating system of the precooling chamber being operable to refrigerate the air stream thereof to a temperature which will cool the comestibles to a temperature slightly above the freezing point of the comestibles but below room temperature, and the refrigerating system of the quick freezing chamber being operable to refrigerate the air stream thereof to a temperature below the freezing point of the ocmestibles.

8. A construction such as defined in claim 7 wherein, an individual variable speed drive is provided for each of the conveyors.

9. A construction such as defined in claim 7 wherein, the condenser coil of the refrigeratin system of the quick freezing chamber is arranged in heat exchange relationship with the evaporator of the refrigerating system of the precoolin chamber. 1

10. A construction as defined in claim 7 where- 'in, each of said refrigerating systems includes a compressor, and the condenser coil of that sysin spaced relation to the inner walls of the pipe tem serving the colder chamber having a sub stantial portion of itslength disposed within and constituting the evaporator of that refrigerating system serving the less cold chamber.

11. An apparatus for freezing comestibles '0 the like comprising, a precooling chamber and a quick freezing chamber, a mechanical refrigeratfreezing chamber having a substantial portion of 12. An apparatus for freezing comesti bles or Y the like comprising, a substantially closed precooling chamber and a substantially closed quick freezing chamber, a, mechanical refrigerating system for cooling each of said chambers, each of said systems including an evaporator disposed within the particular chamber the system is serving, means for circulating in each of said chambers an air stream over the evaporator thereof, means for conveying comestibles through the precooling and quick freezing chambers and across the path followed by the air stre therein and lib delivering them to a point of discharge exterior of the quick freezing chamber, each of said re;- iri'gerating systems including a condenser, the evaporator 01 the system serving the pre-cooling chamber being combined in heat exchange relationship with the condenser of the refrigeratin system serving the quick Ireezing chamber, and

said refrigerating systems being respectively operable to chill the air in the ore-cooling chamber to a temperature which will cool the comestibles therein to a temperature above but closely adjacent their freezing point and the air stream in the quick freezing chamber to a temperature below the freezing point of the comestibles therein. 

